title: Dispersion-enhanced phase noise effects on reduced-guard-interval CO-OFDM transmission.
abstract: Unlike conventional CO-OFDM systems, we show in this paper that reduced-guard-interval (RGI) CO-OFDM systems experience subcarrier-dependent phase noise (PN) from the local oscillator laser. This phenomenon manifests in RGI-CO-COFM systems because the chromatic dispersion (CD) induced walk-off becomes comparable to the OFDM symbol length. We term this phenomenon the dispersion enhanced PN (DEPN). In this work an analytical study of the impact of DEPN on CO-OFDM transmission is conducted. We develop a system-level analytical model and calculate the variance of the dispersion-induced subcarrier-dependent phase rotation term (PRT) using two different distribution patterns of pilot subcarriers (PS). Moreover, we present a bit error rate (BER) estimator to quantify the system performance degradation due to PRT. Numerical simulations are then performed to verify the analytical model. Finally, we propose a grouped maximum-likelihood (GML) phase estimation approach to mitigate the DEPN impairment, and demonstrate a 0.7-1.7 dB SNR improvement at BER=10⁻³ for typical 100 Gb/s RGI CO-OFDM systems.
authors.affiliation: Department of Electrical and Computer Engineering, McGill University, Montreal, QC, Canada. qunbi.zhuge@mail.mcgill.ca
authors.forename: Qunbi
authors.initials: Q
authors.lastname: Zhuge
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.forename: David V
authors.initials: DV
authors.lastname: Plant
mesh_terms: D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008027:Light; D008962:Models, Theoretical; D012542:Scattering, Radiation; D013685:Telecommunications / Q000295:instrumentation*